---
title: "Part-of-Speech Tagging Guidelines for the — Santorini 1990"
description: "These are the annotator guidelines behind the Penn Treebank part-of-speech tag set (NN, NNS, JJ, VBD, VBN and the rest). The report defines each tag and…"
authors: ["Beatrice Santorini"]
year: 1990
venue: "manual"
source: "https://catalog.ldc.upenn.edu/LDC99T42"
licence: "© University of Pennsylvania (Technical Report MS-CIS-90-47), free download from LDC documentation, no licence stated — read only"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/santorini-1990-part-of-speech-tagging-guidelines-penn-treebank/"
---
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# Part-of-Speech Tagging Guidelines for the Penn Treebank Project (3rd Revision)

**Authors:** [Beatrice Santorini](https://md.research.elamur.ai/free/en/authors/beatrice-santorini/) · **Year:** 1990 · **Venue:** Technical Report MS-CIS-90-47, Department of Computer and Information Science, University of Pennsylvania **Link:** unknown (technical report MS-CIS-90-47) **License of the paper:** unknown

[**434** citations](https://openalex.org/works?filter=cites:W900993354) OpenAlex · 2026-10-14 · [**49** citations in our library](https://md.research.elamur.ai/free/en/papers/santorini-1990-part-of-speech-tagging-guidelines-penn-treebank/cited-by/) of the 140673 papers whose bibliographies we read · [manual](https://openalex.org/S4306402083)

- [Publisher's page](https://catalog.ldc.upenn.edu/LDC99T42)
- [PDF](https://catalog.ldc.upenn.edu/docs/LDC99T42/tagguid1.pdf)
- [OpenAlex](https://openalex.org/W900993354)

**Authors (1)**

1. [Beatrice Santorini](https://openalex.org/A5023146320) h 14 · 2138 citations · 47 works

Citations and author metrics: OpenAlex, 2026-10-14; authors with the same name are not always told apart.

## Summary

These are the annotator guidelines behind the Penn Treebank part-of-speech tag set (NN, NNS, JJ, VBD, VBN and the rest). The report defines each tag and, more importantly, gives decision procedures for the hard cases that make tagging inconsistent: adjective versus noun, past tense versus past participle, particle versus preposition, and similar confusions. The tests are mostly substitution and modification tests, for example whether a word can be intensified by "very" or can take a plural ending. Many short examples illustrate each decision. The document became the de facto reference for English PTB-style tagging and is still the authority behind the XPOS column of English UD treebanks.

## How Mova uses it

- `en/seeds/` — the English grammar seeds (short declarative rule notes with conditions, exceptions, examples and sources) cite the guidelines as the authority for PTB tag decisions; about 43 seed files reference it, mostly under `en/seeds/morph/` (noun number, verb forms, adjective degree, pronouns, word formation) plus a few in `nominal/` and `verbal/`.
- Example: [en/seeds/morph/adj-as-noun.md](https://mova.elamur.ai/free/en/docs/en/seeds/morph/adj-as-noun/) uses the "(very) rich" test from §4.1 to separate partial conversion ("the rich" stays JJ/ADJ) from full conversion ("natives" becomes NNS/NOUN).
- The seeds combine the guidelines with classic descriptive grammars, so a tagging rule always carries both a linguistic rationale and the PTB convention it must produce.

## Effectiveness in Mova

Reference material for rule writing: it defines the target conventions rather than a technique. Not measured separately.

---

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Topics: [Treebanks](https://md.research.elamur.ai/free/en/topics/treebanks/) · [Part-of-speech tagging](https://md.research.elamur.ai/free/en/topics/part-of-speech-tagging/)

## Cite

The paper itself, not this card. BibTeX from the library's record of the work.

```bibtex
@book{santorini1990part,
  title = {{Part-of-Speech Tagging Guidelines for the Penn Treebank Project (3rd Revision)}},
  author = {Santorini, Beatrice},
  year = {1990},
  url = {https://catalog.ldc.upenn.edu/LDC99T42}
}
```

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